This invention relates to a device which is used for sampling fluids which are to be analyzed by a laboratory instrument. Although many applications are contemplated, the one used to describe the operation of the device is for analysis of sampled blood. The blood is normally collected by using a syringe to draw the blood or by collecting the blood in a glass capillary tube.
The currently available analytical instruments use three methods of delivering the blood sample to the instrument. First, if a syringe is used, the sample might be injected into the instrument sampling port. There is much variability in this approach, due to the fact that (1) the force used to inject the sample may vary from operator to operator, (2) the force used to inject the sample into the instrument may vary from test to test, (3) the force may vary throughout the injection of a single sample, and (4) the sample size may vary from test to test.
Second, some instruments aspirate the sample from the syringe. For these instruments to be operable, a sampling probe protruding from the instrument must be manually aligned with the syringe carrying the blood. This approach takes much time, demands manual dexterity on the part of the user, requires cleaning the probe after each use to avoid cross-contamination of samples, risks skin puncture of the technician by the probe, and risks exposure of the technician to blood overflow.
Third, if the sample is introduced via a capillary, it is necessary in some instruments to attach a special adaptor to the capillary so that the sample can be drawn from the capillary by a vacuum drawn by the instrument. This requires time to connect the adaptor, risks exposure of the technician to potentially contaminated blood, and requires manual cleaning or disposal of equipment, including the adaptor. In some instruments the operator is forced to hold and maintain a seal with the sample entry throughout the aspiration process.